New control for high blood pressure is sought

National study focuses on patients who don't respond to hypertension medication

June 19, 2012|By Jessica Tobacman, Special to the Tribune

Dr. Keith Benzuly and patient Carolyn Campos are part of a national study on hypertension. (Brent Lewis, Special to the Chicago Tribune)

Chicagoan Carolyn Campos has been on a roller coaster with her blood pressure for about five years.

"I get really bad headaches, to the point where I have to sit in a dark room, and my eyes hurt," said Campos, 59. "It was been happening a lot more often than I would like."

She is hopeful, however, that a new nationwide study in which she is participating will offer her a way of controlling her hypertension, and will at least allow her to take fewer than five medications, three times each day.

"I'm trying to help other people," she said. "It's exciting, especially if it can help control blood pressure and get you off some of the medications."

Dr. Keith Benzuly, a cardiologist and principal investigator of the portion of the study being conducted at Northwestern Memorial Hospital's Bluhm Cardiovascular Institute, calls the study "a potential ray of hope."

About 30 percent of adults in the United States older than 18 have hypertension, according to the American Medical Association's Journal of Ethics.

"It is very prevalent," Benzuly said. "It's a major risk factor for strokes, heart attacks and heart failure. Current therapies are not completely effective."

About 10 percent of patients with hypertension, or more than 7 million Americans, have hypertension resistant to medications, according to the American Council on Science and Health. These individuals are taking at least three medications at maximum doses.

A treatment called renal denervation may help such patients lower their blood pressure.

There were two previous, relatively small trials using the renal denervation therapy, which uses a catheter system to treat high blood pressure.

"It was effective at decreasing (systolic) blood pressure by as much as 30 points," Benzuly said. "Most (patients) responded and responded dramatically. In addition, it appears to be safe."

Normal blood pressure is less than 120 systolic and less than 80 diastolic. People with readings somewhat higher are considered to have pre-hypertension. Those considered to have high blood pressure — hypertension — have readings of 140 or higher systolic or 90 or higher diastolic, according to the National Heart, Lung and Blood Institute of the National Institutes of Health.

"After the initial treatment, patients had a really dramatic decrease in blood pressure, not generally achieved with medications," said Dr. Melissa Robinson, director of electrophysiology services at the University of Illinois Hospital and Health Sciences System. "Hopefully the larger trials will show us that not only can we achieve a drop in blood pressure but also reduced mortality and morbidity in patients."

The latest trial is a much larger follow-up to the other two studies.

"It is intended to be the pivotal trial in the U.S., to confirm the safety and efficacy for refractory hypertension. We're very excited about this technology," Benzuly said.

The trial is a controlled study. A goal is to enroll 530 patients like Campos in as many as 90 hospitals, according to Medtronic Adrian LLC, which manufactures the Symplicity Catheter System and is sponsoring the study.

The major criteria for patients interested in being part of the trial are to be age 18 to 80, have a systolic blood pressure greater than 160 despite taking at least three medications at fully tolerated doses, and not have severe kidney failure.

During the long term, blood pressure regulation is somewhat dependent on the kidneys and the renal nerves, which share information between the brain and the kidneys. Patients who have hypertension also have hyperactive renal nerves, which increase blood pressure.

The procedure involves inserting a small tube into an artery in the groin "to make sure that the arteries are suitable for treatment," Benzuly said. "If they are suitable, then we'll place through a catheter a small, radio-frequency electrode in the kidney artery, deliver radio-frequency energy, which modifies the nerves on the outside of the artery. We'll perform that modification to each kidney."

The physicians then remove the tubes. The patient remains in the hospital overnight and returns home the following day, later making office visits to see how well blood pressure is controlled. For three years, patients will be monitored to see how effective the procedure is at controlling blood pressure, and how safe it is.

If patients are part of the control group for the study, meaning that they are not treated with renal denervation initially, then, after six months, they can cross over from simply taking medications to receiving the treatment.

Renal denervation is being marketed and clinically used in Europe. It is currently considered an investigative therapy in the United States, Benzuly said.

"If we can get this approved and be able to do it in the U.S., it would be really good," Campos said. "I like helping people, and if this is a way I can do it, I'm all for it. It's exciting. It's something new. If it's something that's going to help us, that's great."